1. Field of Invention
The present invention relates to an electrooptic device and a production method therefor. More particularly, the present invention relates to an electrooptic device which is suitable for use in a portable telephone, a mobile computer, and the like, and in which the effective voltage to be applied to liquid crystal is high, high-contrast display is possible, and a reflective electrode and a reflective plate are prevented from deteriorating. The invention also relates to a production method for the electrooptic device.
2. Description of Related Art
Electrooptic devices (for example, liquid crystal display devices and EL light-emitting display devices) are widely used as direct-view display devices in various electronic devices, such as portable telephones and mobile computers. For example, in an active matrix semi-transmissive and semi-reflective liquid crystal display device of such electrooptic devices, a TFT array substrate and a counter substrate opposing each other are bonded with a sealing material, and liquid crystal serving as an electrooptic substance is sealed and held between the substrates in a region defined by the sealing material.
A reflective plate is formed on the surface of the TFT array substrate so as to reflect external light incident from the counter substrate side back toward the counter substrate, light incident from the counter substrate is reflected by the reflective plate of the TFT array substrate, and an image is displayed with the light emitted from the counter substrate (reflection mode). The reflective plate has an opening to transmit light, a transparent electrode is formed under the reflective plate so as to cover the opening, and an image is displayed with light from a backlight passing through the opening (transmissive mode).
A TFT array substrate 120 used in such a liquid crystal display device is, as shown in FIG. 15, formed, for example, by stacking, on a substrate 101, a protective underlayer 102 made of a silicon oxide film (SiO2 film) or the like, a switching element made of a thin-film transistor (TFT) 103 or the like, a gate insulating film 103a, a source line 104, an interlayer insulating film 105, a protective film 105a made of a silicon nitride film (the protective film 105a is sometimes not formed), two layers made of organic photosensitive resin, such as acrylic resin, to form surface irregularities for reflection under a transparent electrode 108, which will be described below, that is, a surface-irregularities forming layer 106 and an uneven layer 107, a transparent electrode 108 made of an ITO (Indium Tin Oxide) film, and a reflective plate 109 made of a single film of aluminum, silver, or an alloy thereof, or a composite film formed of the metal or alloy, and titanium, titanium nitride, molybdenum, or tantalum. The source line 104 and the transparent electrode 108 are electrically connected by a contact hole 110 formed through the uneven layer 107. On the other hand, in a counter substrate 130, a transparent electrode 132 made of an ITO (Indium Tin Oxide) film is formed on a substrate 131. Alignment films 111 and 133 are formed on the surfaces of the TFT array substrate 120 and the counter substrate 130 in which they face liquid crystal 50.